As electronic products trends to be smaller, multifunctional and environmentally friendly, people attempt to product an electronic system with smaller size, higher integration level, as well as having more comprehensive functions. Therefore, the processing of thin chips and thin device wafers becomes the bottleneck in volume production of ultra-thin products, which brings about a temporary bonding and debonding method.
The temporary bonding and debonding method has following advantages. Firstly, a carrier chip wafer provides mechanical support and protection to a thin device wafer, in which way the back-processing could be performed through equipment from a standard device wafer manufacturer, so that the ultra-thin device wafer is able to be processed at the wafer level. Hence, Equipment from the device wafer manufacturer is able to process the ultra-thin device wafer by a temporary bonding and debonding technique, and there is no need to refit the equipment or employ particular termination effector, fixture or device wafer cassette.
The temporary bonding technology has solved problems as the thin wafer holding issue and fragment production issue during processing. However, there is a high risk of the fragments production when the wafers are separated since multiple uncertainties exist during the separation process. Until now, the medium treatment methods of wafer separation include laser treatment, heat treatment and ZoneBOND etc, yet there are some disadvantages. The laser treatment is limited to the situation that the carrier wafer is made of glass so that the application scene is restricted. Certain warping of temporary bonding wafers appears during heating process, plus heating budget need be considered, the heat treatment is therefore barely applied by manufacturers. On another aspect, the ZoneBOND technology is relatively popular, however, the debonding process has a disadvantage, it requires long pre-brew, which influences productivity and make the volume production impossible.
There are also some other debonding methods in prior art. A technical scheme in a US patent whose publication number is U.S. Pat. No. 8,267,143 B2 decreases the viscosity of an adhesive between a device wafer and a carrier wafer through laser treatment and then separates the adhesive from the wafers by an upward mechanical force. Another technical scheme in a US patent whose publication number is US patent U.S. 2012/0234407A1 mentioned separating the adhesive from the wafers by the relative rotation of the device wafer as well as an upward mechanical force after decreasing the viscosity of the adhesive. However, the mechanical strength of the wafers after thinning is too low to undertake the viscosity during the separation process of the wafers, so that the risk of the fragments during the separation process cannot be effectively solved. Moreover, as the thickness of the wafer after thinning is reducing, there are more difficulties during the debonding process.
Therefore, it is necessary to provide a new mechanical debonding method and system in order to solve those technical problems described above.